Under present circumstances where distribution of contents such as digitized movies and music has started in earnest, it is urgently required to realize a mechanism to manage copyrights and licenses concerning this type of contents.
One can not sell or transfer contents such as movies or music (that is, material that has a copyright) in order to make profit unless the contents are licensed by the copyright holder ever since the Copyright Act was enacted. The contents here means digital contents that have such a structure as a collection of bit arrays recordable on a single piece of recording media, such as documents, still images, video, and software programs.
This type of contents is distributed to users in a state where the contents are recorded on recording media. In this case, controls for access to the contents (henceforth, contents access control) are provided using license information for the purpose of protection of their copyrights. This contents access control is provided in order that only an authorized user can get access to the contents.
As an example of contents access control, there is one realized by using license information consisting of identifying information that identifies each of physical elements (that is, system elements such as recording media, device) required for accessing the contents. This license information includes license conditions for the access to contents. Such a system has identifying information allocated specifically to that system. A user gets the license information from a channel different from a channel from where he gets the contents. The user then inputs the license information into the system, and sets the recording media, that contains the contents, into this system.
The system determines whether the identifying information allocated to he system satisfies the license conditions included in the license information entered by the user. When the information satisfies the license conditions, access to the content is allowed. On the other hand, when the information does not satisfy the license conditions, the access to the contents is not allowed.
As explained above, when accessing the contents in a conventional manner, it is required to acquire both the recording media that contains the contents and the license information from different channels, which is extremely inconvenient. Further, the recording media and the license information exist separately, which may cause either of the two to be lost in the conventional system.
Further, conventionally, only the license information exists as a single unit. Therefore, unauthorized duplication of the license information is possible, and as a result, there has been a problem that unauthorized access to the contents may occur. This is not good from the viewpoints of protection of copyright holders.